Storage of 8M Urea buffer?

I made a some 8M Urea buffer two weeks ago and since then Ive had it at room temperature. I read somewhere that u used always make it fresh and/or store it at 4C? Is this true then I cant use my big bottle of buffer

I made a some 8M Urea buffer two weeks ago and since then Ive had it at room temperature. I read somewhere that u used always make it fresh and/or store it at 4C? Is this true then I cant use my big bottle of buffer